1 Chronicles 23:3-5

3And the Levites were numbered from thirty years old and upward; and their number, by their polls, man by man, was thirty-eight thousand.

4Of these, twenty-four thousand were to preside over the work of the house of Jehovah; and six thousand were officers and judges;

5and four thousand were doorkeepers; and four thousand praised Jehovah with the instruments which I made, [said David,] to praise [therewith].